Risk analysis within the Codex system is carried out by a number of different bodies. Some of these are subsidiary to the CAC and include the Codex Committees on Food Additives and Contaminants; Pesticide Residues; Residues of Veterinary Drugs in Foods; Food Hygiene; Meat Hygiene; Food Import and Export Inspection and Certification Systems; and Nutrition and Foods for Special Dietary Use. These are intergovernmental bodies, whose tasks are to prepare draft standards, guidelines and recommendations for consideration by CAC.
Scientific input into the Codex decision-making process is routinely provided by independent expert bodies, including the Joint FAO/WHO Expert Committee on Food Additives (JECFA) for additives, chemical contaminants and veterinary drug residues and the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) for pesticide residues. Codex committees from time to time also draw on advice from other bodies outside the Codex system, for example, the International Commission on Microbiological Specifications for Food (ICMSF).
Risk management issues are normally discussed within Codex committees but on rare occasions JECFA has issued recommendations in this area. Risk communication is usually dealt with by Codex committees, Member States and nongovernmental organizations (NGOs). A discussion of the risk analysis process within Codex can conveniently be divided into the following areas:
- food additives
- chemical contaminants
- pesticide residues
- veterinary drug residues
- biological agents
In describing practices in the existing Codex system, risk assessment terminology as defined by the Consultation has been used, with the recognition that in some cases, Codex risk assessment activities are deficient and/or inconsistent with these definitions.
The risk analysis procedure for food additives is usually initiated by the Codex Committee on Food Additives and Contaminants (CCFAC) when it proposes additives for evaluation by JECFA. This process may also be triggered by direct requests to FAO/WHO from member countries. The initiation of the evaluation procedure serves as the hazard identification step.
JECFA carries out toxicological evaluations of food additives, normally resulting in an estimate of the amount of the additive, expressed on a body weight basis, that can be ingested daily over a lifetime without appreciable health risk (notionally "zero" risk). This is referred to as the ADI. In setting an ADI, a safety factor is applied to the no-observed-effect level (NOEL) determined in the most appropriate (usually the most sensitive) animal species (WHO, 1987). JECFA does not make a quantitative estimate of risk at an intake corresponding to the ADI, but concludes that the risk is so small as to be negligible from a public health point of view. The toxicological evaluation can be considered to be mainly the hazard characterization step.
There are occasions when JECFA considers the use of an ADI in numerical terms not to be appropriate. This situation arises when the estimated consumption of me additive is expected to be well below any numerical value that would ordinarily be assigned to it. Under such circumstances, JECFA uses the term "ADI not specified". JECFA defines this term to mean that, on the basis of available data (chemical, biochemical, toxicological, and other), the total daily intake of the substance, arising from Us use at the levels necessary to achieve the desired effect and from its acceptable background in food, does not, in the opinion of JECFA, represent a hazard to health. For that reason, and for the reasons stated in the individual evaluations, the establishment of an ADI in numerical form is not deemed necessary.
When JEFCA has recommended an ADI for an additive, CCFAC is then able to endorse the use of the additive in specific foods at defined use levels. Proposals for such use and use levels often come from Codex commodity committees. The use level is based on the amount needed to achieve a desired technological effect in the food. Until recently, the CCFAC has worked on an ad hoc commodity-by-commodity basis, without consideration of the overall use of the additive. However, CCFAC is currently developing a General Standard for Food Additives (GSFA) covering the use of additives in all foodstuffs. CCFAC has also had an ad hoc working group on food additive intake.
In the current process, the establishment of levels of use for additives takes little account of the potential total exposure to the additive concerned. However, the approach recommended to be used in the GSFA provides the framework in which exposure assessments will be considered.
For the purposes of this discussion chemical contaminants comprise industrial and environmental contaminants (e.g. heavy metals, persistent organo-halogen compounds) and naturally occurring toxicants (e.g. mycotoxins).
Within the Codex system, risk analysis of chemical contaminants is normally initiated by CCFAC but occasionally it may be initiated by member countries as in the case of additives. This serves as the hazard identification step.
The toxicological evaluation is carried out by JECFA and normally results in the estimation of a Provisional Tolerable Weekly Intake (PTWI) or Provisional Maximum Tolerable Daily Intake (PMTDI). This corresponds to the hazard characterization step. As in the case of ADIs (see 4.1 Food additives), these are health-based estimates of the intakes associated with negligible risk. While ADIs are intended to be used in allocating the acceptable amounts of an additive for necessary technological purposes, trace contaminants have no intended function, so the term "tolerable" was seen as a more appropriate term than "acceptable". This is intended to signify permissibility rather than acceptability for the intake of contaminants unavoidably associated with the consumption of otherwise wholesome and nutritious foods. In this convention, tolerable intakes are expressed on a weekly basis, because the contaminants given this designation may accumulate within the body over a period of time. The PMTDI has been established for food contaminants that are not known to accumulate in the body, such as tin, aresenic and styrene. The use of the term "provisional" expresses the tentative nature of the evaluation, in view of the paucity of reliable data on the consequences of human exposure at levels approaching those with which JECFA is concerned. As in the case of additives, they are based on the determination of a NOEL and the application of safety factors. This approach assumes that there is a threshold, i.e., a dose level below which no significant adverse effects will occur. In cases where no threshold is thought to exist (e.g. contaminants, such as aflatoxins which are genotoxic carcinogens), JECFA does not allocate a PTWI or PMTDI. Instead it recommends that the level of the contaminant in food should be reduced to as low as reasonably achievable (ALARA). The ALARA level, which may be viewed as the irreducible level for a contaminant, is defined as that concentration of a substance that cannot be eliminated from a food without involving the discarding of that food altogether or severely compromising the ultimate availability of major food supplies.
The question of establishing maximum levels for chemical contaminants in food is considered by CCFAC in consultation with Codex commodity committees. Exposure assessments for contaminants have been carried out by JECFA, CCFAC and GEMS/Food as well as by national bodies, and these assessments have been used in the development of Codex maximum levels or, in some cases, guideline levels. CCFAC is currently developing a General Standard for Contaminants (GSC) based on risk assessment and risk management principles, which will provide the framework for the routine incorporation of exposure assessment into the standard setting process.
The risk analysis procedure for pesticide residues is usually initiated by the Codex Committee on Pesticide Residues (CCPR) when it proposes specific pesticides for evaluation by the JMPR. The process may occasionally be triggered by direct requests from member countries or industry to FAO/WHO. The CCPR has also established procedures for the re-evaluation of selected pesticides.
The JMPR carries out toxicological evaluations of pesticide residues, normally resulting in an estimate of the ADI (WHO, 1990). In addition, JMPR proposes Maximum Residue Limits (MRLs) for individual pesticides in or on specific commodities. These MRLs are primarily based on the residue levels estimated in supervised field trials when the pesticide is used according to Good Agricultural Practice (GAP).
Using the MRLs, preliminary exposure estimates are made and compared with the ADIs (GEMS/Food, 1990). GEMS/Food currently performs the calculations of the Theoretical Maximum Daily Intake (TMDI) based on the MRLs and estimates of commodity intake based on a global diet. This calculation is known to greatly overestimate the exposure and is conducted for screening purposes. If the TMDI exceeds the ADI, the Estimated Maximum Daily Intake (EMDI) is calculated based on global and regional diets and may include correction factors to improve the accuracy of exposure estimates. For example, data on the edible portion of the food and the fate of residues during processing may be used to make a more accurate calculation of exposure. GEMS/Food also collects data on the actual exposure to pesticides, but such data are mainly limited to developed countries and are often not comparable (GEMS/Food, 1988, 1992).
The ADIs and MRLs recommended by JMPR are then considered by the CCPR and on occasion the MRLs are modified before they are forwarded to the CAC for adoption. The CCPR also estimates exposure by a variety of methods. In cases where initial estimates indicate that the ADI may be exceeded, more refined intake calculations are performed using national food consumption data and information from pesticide residue monitoring programmes.
The risk analysis of veterinary drug residues is normally initiated by the Codex Committee on Residues of Veterinary Drugs in Foods (CCRVDF). The process may also be triggered by direct requests to FAO/WHO from member countries. This represents the hazard identification step.
JECFA carries out toxicological evaluations of veterinary drugs and normally derives an ADI in the same way as for food additives. The NOEL from the most sensitive animal model is usually used. However, antimicrobial activity may become the end-point for setting the ADI when residues of an antimicrobial veterinary drug ingested in food may disrupt intestinal flora and impact on human health. This corresponds to the hazard characterization step.
JECFA also estimates potential intake of residues of veterinary drugs using standard assumptions about the consumption of edible animal products, such as meat and milk, and proposes MRLs that are consistent with Good Practice in the Use of Veterinary Drugs (GPVD). These estimates of potential intakes are compared with the ADIs. This is the risk characterization step.
The MRLs proposed by JECFA are circulated to Governments by the CCRVDF, whose primary role is to formally recommend MRLs. Scientific issues are not discussed in detail at CCRVDF but risk management options may be considered in the light of government comments.
Biological agents (bacteria, viruses, helminths, etc.) have not been the subject of systematic risk analysis by the CAC. Foods have, however, been studied on a case-by-case basis when potential pathogens have been identified as being of concern to public health and international trade. Since the mid-1970's the Codex Committee on Food Hygiene (CCFH) has used a qualitative approach in identifying foodborne hazards, using principally the qualitative risk descriptions proposed by the ICMSF and matching these to foods associated with specific outbreaks of foodborne illness or to foods which were known historically to be associated with such outbreaks. The recommendations of the CCFH have been in the form of Codes of Hygienic Practice, often supplemented by advisory microbiological specifications which are used to verify that the control processes described in the code have been carried out properly. End-product specifications were assumed to be particularly useful for examining products of unknown origin. Codes of Hygienic Practice were frequently developed in consultation with specific Codex commodity committees.
Meat hygiene has also been the subject of a commodity-specific approach by the Codex Committee on Meat Hygiene (CCMH). However, a very different risk-based approach has been used in developing Codes of Hygienic Practice and, in particular, the Code for the Ante-Mortem and Post-Mortem Judgment and Post-Mortem Inspection of Meat.
More recently, the CCFH has examined certain pathogens, such as Listeria monocytogenes, from the point of view of their occurrence in the diet. Although this has not, as yet, resulted in the development of recommendations for the control of these organisms, the first steps have been taken in establishing a risk-based approach for developing international recommendations.
The Codex text on the Hazard Analysis Critical Control Point (HACCP) system developed by the CCFH requires the use of risk-based decision making in identifying significant hazards at different points in the food processing chain and establishing critical limits at specified critical control points. This system is being integrated into the Revised General Principles of Food Hygiene and will be applied to other existing Codes of Hygienic Practice.
The Codex Committee on Import and Export Food Inspection and Certification Systems (CCFICS) has confirmed that risk-based approaches should be used in the development of national food import inspection systems. Such approaches will target problem areas more effectively and provide greater consumer protection than systems based purely on random inspection procedures. Detailed protocols have yet to be developed.